1. Field of the Invention
The present invention relates to a method for operating a poultry defeathering apparatus, where a drive mechanism is used for rotating a plurality of picking heads, and to a picking bank comprising at least one cover member, a plurality of picking heads and a drive mechanism for rotating the picking heads, each of said picking heads being mounted at an outer side of the cover member on an axle projecting through an opening in the cover member, said axle being supported by a bearing, and said drive mechanism being arranged on a inner side of the cover member opposite the picking heads.
2. Background
Such poultry defeathering apparatuses have been known for decades, but have been the subject of continuous development, a recent example of an improved apparatus being described in the applicants own patent application WO2007071236.
The overall construction of the picking banks with rotating picking heads driven via axles projecting through a cover member, typically in the form of a housing enveloping at least a part of the drive mechanism, has remained largely unchanged. Accordingly, the need for protecting the drive mechanism and particularly the axle bearings, which must work constantly under very tough conditions, including the exposure to water, feathers and sand dust, and for preventing feathers and dirt from building up inside the picking bank, has long been recognized. Sand dust and small feathers measure only micro millimeters and can penetrate the smallest clearance and enter the internal of the picking bank. This effect is enhanced by the usage of large amounts of water on the outside front of the picking banks to assist the feather removal, since moisture will follow the sand dust and feathers and cause bearings to rust, thereby reducing their lifetime considerably.
Examples of solutions to these challenges are found in U.S. Pat. No. 4,175,302, which discloses the use of a sleeve around the axle, and in U.S. Pat. No. 7,175,516, which teaches the use of a set of three seals at each axle. The inventions in these two publications, which represent a span of 25 years of development within this field, and other like them function very well in theory, but in practice they lack the robustness desired in modern poultry processing industries. As also explained in U.S. Pat. No. 4,175,302, fine feathers are able to penetrate into the smallest of openings and are surprisingly abrasive, thus causing the need for frequent maintenance and repair, and this remains a problem even when the prior art solutions have been applied. Particularly the axle seals will wear out over a short period of time due, not least due to an often high content of sand dust in the feathers, and it is both time consuming and expensive to replace them. Moreover, attempts to clean the inside of picking banks have been know to in itself result in damage to the mechanical parts, bearings and seals.